I think you are worrying far too much about it.
Surely you don't want to jeopardise the chance of having her live here with her MOTHER do you ?
It is THAT serious.
What happens if you leave her behind and then YOU miss her so much that you are crying every day here...as happened with my ex-wife ?....THEN get turned down for a dependent visa because the UKBA decide that you no longer have sole responsibility for her ?
On the hand, if she does not like it here, at least she can go back to the Phils anytime.